<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
        "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    <title>Test</title>
    <script type="text/javascript" src="jquery-1.7.1.min.js"></script>
    <script type="text/javascript">
        $().ready(function() {
            $("#btn").click(function(){
                var aaa = $("#SERVICE").attr("checked");
                alert('aaa:'+aaa);
            });
        });
    </script>
</head>
<body>
<input name="SERVICE" id="SERVICE" type="checkbox">OK
<input id="btn" value="button" type="button">
</body>
</html>